Many types of automatic transmissions use multiple gear sets, frequently planetary-type gears, with brakes and clutches, often in the form of bands. The respective brakes and clutches are operated by servo valves. The servo valves, in turn, can be controlled by an electrical control unit in dependence on selected operating conditions, vehicle speed, loading on the internal combustion engine, rapid acceleration conditions, or the like. Such units are constructed to be fail-safe, that is, if the electronic command system should fail, the highest possible gear range is commanded to be connected, usually the direct drive gear. This is generally the case if all the magnetic valves or servo valves are deenergized. This permits forward movement of the vehicle. It is not possible, however, to reverse or move the vehicle by pushing it. This is a disadvantage especially if the failure should occur while the vehicle is operated in traffic and can be removed from a traffic lane only by pushing or pulling, or by moving the vehicle rearwardly.